Interpretive Summary: Of consumer articles made mostly from non-renewable resources, petroleum-based synthetic plastics constitute the largest such category of municipal solid waste in the United States. Containers and packaging products represent the largest group within plastic waste in municipal landfills. Because of this, efforts are being made worldwide to search for renewable and biodegradable substitutes for petroleum-based plastics. Starches, derived from surplus commodity crops, have been investigated as a possible replacement, but it does have some disadvantages such as its susceptibility to water owing to its highly hydrophilic nature. To improve its water resistance, we have studied the properties of baked starch foams with added natural rubber latex. The starches investigated were wheat, potato, and waxy corn. Stabilization of the latex with non-ionic detergents helped prevent irregularities in the foam product. Latex does decrease the effect of higher humidity on the foam products. The mechanical properties of these foams are comparable to commercial products and can be adjusted by varying the ingredients.

Technical Abstract:
Of consumer articles made mostly from non-renewable resources, petroleum-based synthetic plastics constitute the largest such category of municipal solid waste in the United States. Containers and packaging products represent the largest group within plastic waste in municipal landfills. Because of this, efforts are being made worldwide to search for renewable and biodegradable substitutes for petroleum-based plastics. Starches, derived from surplus commodity crops, have been investigated as a possible replacement, but it does have some disadvantages such as its susceptibility to water owing to its highly hydrophilic nature. To improve its water resistance, we have studied the properties of baked starch foams with added natural rubber latex. The starches investigated were wheat, potato, and waxy corn. While latex does increased the density of the foam, it also improved the flexibility of the product. Stabilization of the latex with non-ionic detergents helped prevent irregularities in the foam product. The flexural properties of these foams are comparable to commercial products and can be ‘tuned’ by varying the starches and adjusting the latex concentration. Latex also decreases the equilibrium moisture content and decreases the effect of higher humidity on the foam products.